@import 'prefix.scss';
@each $mrg in (5,10,15,20,25,30,35,40) {
  .#{$prefix}-m-#{$mrg} {
    margin: #{$mrg}px;
  }
  @each $dir,$name in ('r','right'), ('l','left'), ('t','top'), ('b', 'bottom') {
    .#{$prefix}-m#{$dir}-#{$mrg} {
      margin-#{$name}: #{$mrg}px;
    }
  }
}